I've posted it.
Well basically you need to go up to someone and than you just press "F" to take an order.
After that they will drop a paper with a pizza type. If you dont know the recipe of pizza you can look it up on your PC (InGame, PC is right next to cash register), than you just place those things (for example if its pepperoni pizza than youll place 5 pepperoni on pizza, etc...).
Also you'll need to oven that pizza and than you can serve it to a guest that has requested that pizza ^^ (After this they'll give you money, but if you overcook your pizza you wont get the full price of the pizza)
Thanks btw ^^